Genetic diversity and phylogeny of soybean rhizobia isolated from the regions of Loess Plateau in China
黄土高原地区大豆根瘤菌的遗传多样性和系统发育

Abstract: Objective] We investigated the genetic diversity and phylogeny of soybean rhizobia isolated from the regions of Loess Plateau in China. Methods] We analyzed 130 soybean rhizobia isolated from 15 regions in 4 provinces of Loess Plateau through BOX-PCR, 16S rDNA PCR- RFLP, 16S-23S IGS PCR-RFLP and 16S rRNA gene sequencing. Results] BOX-PCR, 16S rDNA PCR- RFLP and 16S-23S IGS PCR-RFLP were in good agreement with the results which showed that all strains tested ascribed to two groups: the genus of Sinorhizobium and Bradyrhizobium phylogenetically. The analysis of 16S rRNA gene of 5 representative strains indicated that they were related to type strains S. fredii, B. japonicum and B. liaoningense, homology coefficient with type strains was 100% respectively. Conclusion] Soybean rhizobia isolated from the regions of Loess Plateau in China showed rich genetic diversity. S. fredii was the dominant species. Bradyrhizobium accounted for 10% of the strains tested only, of which, two strains were B. liaoningense.